Light emitting apparatuses having a plurality of light sources arranged on a surface of a holder are used not only in general illumination but also in various usages such as advertisement, decoration, signaling and the like. In order to form such a light emitting apparatus, it may be conceived to use bullet-type LED light sources having lead wires and a printed circuit board formed with through-holes into which the lead wires of the light sources are inserted and a conductor pattern for transmitting electric power to the light sources, and to connect the lead wires of the light sources to the conductor pattern of the printed circuit board by means of flow soldering.
Such a structure that utilizes a printed circuit board as a holder of the light sources can bring about an economic benefit when manufactured on a large scale. However, in a case that a variety of light emitting apparatuses having different light source arrangements and connection patterns are produced in small quantities, it can rather lead to a higher manufacturing cost. Further, contact with the molten solder in the soldering process will expose the printed circuit board to a high temperature, and this is undesirable to LEDs, which can be easily damaged by heat. Further, the solder typically contains lead, and thus the use thereof necessitates environmental measures. It may be conceived to use a leadless solder, but the leadless solder is higher in price as well as in melting temperature, which can worsen the detrimental effects of heat against the LEDs. Furthermore, the printed circuit board makes it difficult to arrange the light sources on a curved surface. In the case that flexible conductive wires are used to connect light sources, the process of connection may become cumbersome and this can lead to a higher manufacturing cost. The printed circuit board also has a problem that recycling thereof is quite difficult because the printed circuit board has unitary wirings and support board.
To provide a light emitting module without a printed circuit board and solder, Japanese Patent Application Laid-Open No. 7-106634 has disclosed to connect a plurality of LEDs between an anode bus bar and cathode bus bar by means of mechanical engagement. Further, Japanese Patent Application Laid-Open No. 8-316531 has disclosed a light emitting module comprising a plurality of bus bar pairs, a plurality of LEDs attached between each bus bar pair, and flexible joints for electrically and mechanically connecting adjacent bus bar pairs, so that a three-dimensional configuration of the light emitting module is possible. In these laid-open publications, however, there is no disclosure regarding a light source assembly that can allow easy selection of various light source connection patterns and yet can be manufactured with high production efficiency, nor is there a disclosure regarding a manufacturing method therefor.